Flat iron



FIG. 1 is a front elevational view of a flat iron, showing our new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a side elevational view thereof;

FIG. 6 is an elevational view of the opposite side thereof; and,

FIG. 7 is a rear perspective view thereof. 

The ornamental design for a flat iron, as shown and described. 